We prove strong unique continuation property for the differential inequalityIn particular, we establish the strong unique continuation property for V ∈, which has been left open since the works of Escauriaza [6] and Escauriaza-Vega [8]. Our results are consequences of the Carleman estimates for the heat operator in the Lorentz spaces.The sucp for the Laplacian −∆ is better understood. Since the pioneering work of Carleman [3], most of subsequent results were obtained by following his idea, the Carleman weighted inequality. In particular, Jerison and Kenig [13] proved the sucp for the Laplacian with V ∈ L d/2 loc , d ≥ 3. Their result was extended by Stein [28] to potentials V ∈ L d/2,∞ under the assumption that V L d/2,∞ is small enough. Later, Wolff [33] showed that the smallness assumption is indispensable if V ∈ L d/2,∞ . Here, • p,r denotes the norm of the Lorentz space L p,r (R d ) (for example, see [29]).